Effects of different amendment treatments on survival rate and soil microbial community of continuous cropping Atractylodes macrocephala

The results showed that all soil amendment treatments increased A. macrocephala survival rate and yield. Soil fumigation treatment showed the most pronounced effect on plant survival, with a survival rate of 66.9% and a yield of 2533.46 kg·hm-2, representing increases of 89.5% and 157.8%, respectively, compared with the untreated control. The combined treatment of soil burning, fumigation and microbial inoculant application resulted in a survival rate of 61.1% and a yield of 2749.52 kg·hm-2, corresponding to increases of 73.1% and 179.8%, respectively, and showed the largest yield gain among all treatments.

The fungal community structure differed significantly among treatments, while no significant differences were observed in the bacterial community structure. Fungal communities in the control soil were dominated by Basidiomycota, whereas Ascomycota predominated in soils subjected to burning, fumigation, microbial inoculant application and the combined treatment. The combined treatment harbored the most connected fungal network, with 14204 edges, and exhibited a smaller decline in network stability following the removal of keystone nodes, indicating enhanced network complexity and robustness.

Random forest analysis identified Leptosphaerulina, Saitozyma, Paraboeremia, and Fusarium as the key fungal genera associated with A. macrocephala survival, with their relative abundances reduced under fumigation and the combined treatments. Linear regression analysis further showed that the survival rate of A. macrocephala was negatively correlated with the relative abundances of Saitozyma (R2=0.32) and Fusarium (R2=0.22).

Together, these findings indicate that soil fumigation and the combined treatment of burning, fumigation and microbial inoculant application can improve the ecological function of continuously cropped soils by restructuring soil microbial communities, enhancing fungal network stability and suppressing potential fungal pathogens, thereby increasing the survival rate and yield of A. macrocephala.